This invention relates to a pressurized fluid coupling which includes a metal tube having circumferentially extending beads formed therein for receiving a free end of a flexible tube thereon. This invention also relates to a method of manufacturing the pressurized fluid coupling of the present invention.
Pressurized fluid lines and couplings therefor are used throughout a variety of industries, such as in hydraulic equipment applications, refrigeration applications, compressed air applications, and the like. In the automotive industry, high pressure fluid lines and couplings are used in automotive air conditioning systems, braking systems, and power steering systems. The present invention deals primarily with pressurized fluid couplings for use in automotive power steering systems, although the present invention may find use in a variety of applications where there is transfer of pressurized fluid through conduits and hosing.
In an automotive power steering system, a power steering pump and steering gear box are provided wherein the power steering pump delivers pressurized fluid to the steering gear box to aid the driver in steering the vehicle. Typically, both the power steering pump and the steering gear box each include outwardly extending metal conduits or tubes. The ends of these tubes are connected to one another by flexible rubber hose. A metal sleeve is provided adjacent the end of each tube for receiving an end of the flexible hose, the sleeve being compressed or swaged inwardly upon receipt of the hose end to secure the hose end to the tube.
A problem arises in the swaging of the sleeves for fixing the hose ends to the tubes in that during the compression or swaging step, the ends of the metal tubes may become crimped or closed shut, thereby preventing proper operation of the power steering system.
One coupling has been developed which uses a sleeve member for being brazed to the end of a tube. The sleeve member has an inner cylindrical member which is in fluid communication with the tube. The sleeve member includes a housing spaced from the inner cylindrical member which forms an annular passage therebetween for receiving the end of a flexible hose. Upon receipt of the end of a flexible hose, the housing is swaged inward to fixedly secure the end of the flexible hose to the sleeve member.
Another type of pressurized fluid coupling includes the brazing of an outwardly ribbed cylindrical member to the end of the tube. The outwardly ribbed cylindrical member extends outwardly from the end of the tube and receives the end of a flexible hose about the ribbed surface thereof. A conventional cylindrical sleeve is placed about the end of the flexible hose and swaged inward to compress the end of the flexible hose against the ribbed cylindrical member for attaching the flexible hose to the end of the tube.
Still another type of pressurized fluid coupling includes a cylindrical insert member for insertion into the end of the tube to add strength to the end of the tube. The tube has grooves ground in an outer surface thereof for receiving the end of the flexible hose. This insert member is pressed into the end of the tube. A sleeve is placed about the end of the flexible hose and swaged inward to fix the flexible hose to the end of the tube.
The pressurized fluid couplings discussed above require for additional parts to be added to the ends of the tubes for receiving the end of a flexible hose. Additional parts are required for withstanding the compression forces generated during the swaging of the sleeve element about the end of the hose for retaining the end of the hose to the tube. Not only do these additional members add cost to the coupling, but also additional brazing and/or pressing steps are required for attaching the members to the ends of the tubes.